Well guys I am lost. I just got my first big block chev and I am lost. Its a mark IV 454. As far as I know it has stock oval port heads. Anyway to destroke this to a 427? What are the differences between the 454 and the 427? Anyone have recommendations on heads? the only current internal change has been the comp cams thumpr series cam. I plan on running a tunnel ram with dual 500cfms. Sorry if I sound lost but all I have built in the past is smallblocks and aircooled vws. thanks everyone
The main difference is the shorter stroke(4" vs. 3.75"). To make a 427, just change out the crank. As far as heads, it depends on what you want to do with it. Is the tunnel ram and 2X4's for looks? Or are you hoping to "haul the mail" with this engine? If it has peanut ports heads, their smaller size will choke the motor beyond mid-range. To find out what heads you have, just google their casting #.
And pistons.....and harmonic damper.....and flexplate/flywheel. It probably wouldn't hurt to balance everthing while you had it apart. Larry T
If it's an early 454 block, you could use a 396-402 crank to make a 427... Just get the other parts that Larry mentioned and your in like flint!!
Just run the 454 as a 454, tell everyone it's a 427. A few guys will be able to tell the difference by looking at the damper, though. Most of the mid 70s-late 80s 454s had peanut port heads. I'd suggest trying to find some 1960s rectangular port iron heads, they work well with a tunnel ram....and even better with a blower. You gotta give us a lot more info about the car, what you want to do with it, how much money you have, etc. if you want good info about what to do.
I do wish it was an early block, its from an 85 suburban block and heads. Am I mistaken in saying that all of the mark 4 blocks are the same or nearly the same?
The oval port heads can make big power with a little work, contrary to popular belief they can be a better street head than the big rectangle port heads. A lot better low end with similar top end after some port work.
I never had any trouble with rectangular port heads. And neat intakes for them are easier to find. Although from what I've heard, it's not a big deal to run a rect port intake on the normal (not peanut) oval port heads. "the" engine to have is a hi perf 427, rectangular port heads, steel crank, forged pistons, 11:1ish compression, sold lifter flat tappet cam, etc. For a big block hamb car, that is
Squirrel, I think I'd rather have a 540 or 565 cubic inch "396". Hey, they all look the same on the outside. (G) Larry T
You can make a 427 like the others have said. If you're mixing BB parts you need to pay attention to the combustion chamber size of the head as they vary. Then match your head/piston shape to achieve your desired compression ratio. I've always liked the early 70's open chamber heads as they're a little more "Hemi" like in design and good for a few free HP.
I agree leave it as a 454. Why do a bunch of work to lose cubic inch? Here's my 582 cubic inch "396".
come on guys get back on topic, My plans for the car is to drag it, most of the tracks around here are 1/8 mile but it will see some 1/4 fun. I will also be pissing off the neighbors, cops, old people and scaring small children by driving it on the street. My budget is about 1500 to 2000 but labor is free. I will most likely be keeping the bottom end the same even though I do have access to a NOS 1967 427 crank and balancer. the intake is stock with two risers for the carb (ghettto fab) stock heads, going to pull the casting number now and stock bottom end. Anyone have any particular heads that they prefer? I am going to go to the charlotte autofair early next month and I will be looking for an intake manifold and carb setup. I am still unsure of brand that i would like and what carbs I will run. Most likely twin 500 cfms.
OK, back on topic but you changed the rules on us ("keeping the bottom end the same", $1500.00/$2000.00 budget). If it were me, I'd probably use open chamber, oval port heads (781's are pretty common and a dime a dozen, good chance that's what' on your engine). I'd install a good set of stainless steel valves (might as well bump them up to 2.19/1.88 while you're buying them), do a GOOD valve job, pocket port and port match them to the intake. I'd go with a Victor Jr or Weiand Team G type intake and a 750 carb. Lots of other stuff that really needs done, good pistons, rods (at least rebuilt and good bolts), balance job, etc. After you get all of that figured out and the rpms you want to turn (I'd keep it below 6000 for an engine that was gonna be "street reliable") I'd call my favorite cam company and get a cam recommendation from them and follow it. By now we've probably doubled the budget, so I guess we'd better stop. Larry T
Thanks Larry, all that does seem a bit out of my price range but all good things to keep in mind for the long haul
I think that was a suggestion to drop by your favorite book store and buy one, or maybe pick one up from Amazon.com. Books will give you information you can return to and the advise will be the same each time. Not to say the advise on here won't be good it's just that a good technical book will give you all of the basic stuff you need to know. My .02 cents on that issue. Charlie
i was going suggest if your in the "stroking" mood....bump it up to a 496. the cranks are pretty reasonable in cast form.
books kinda helped with building my first 396 way backin the seventies....had these at the house...many more at the shop....just sayin....
My favorite, but it's a bit outdated...which makes it very good for an old fashioned street machine. I bought it new for $5 in 1978, right after I bought my first 396 from the junkyard for $65
Can tell you from past experience, if you build a 427 from a 454 with a 396 crank, and use a stock weight 427 piston, you will need a slug of mallory metal to get it to balance. Well worth it, I love 427's. Much easier on the bottom end.
I got that book and the newer version which is now outdated too...lol CarCraft has a few 454 builds in their tech section, here's just one http://www.carcraft.com/techarticles/116_0109_542hp_big_block_chevy/index.html
" I will most likely be keeping the bottom end the same even though I do have access to a NOS 1967 427 crank and balancer." I would certainly snag that crank as all 427 cranks are forged. Around here they getting very hard to find and at the very least would make excellant trading material.
I would leave it stock, use the thumper cam, invest in a "wet" kit and spray a 100 on it and have reliable tire shredding fun.
Just wondering - how long is a BBC? Tip of the water-pump to rear of the block. I need to recess my firewall, and was wondering if a 396-527-454 would fit into it.
The Way I see this Freshen motor single four barrel. Have fun Keep it simple. My Buddy has a 632 BB chevy single SV1 carb Makes 1200 hp so you don't need two fours. Simple is better! Good luck!
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